Okay, I think this instance was jumping the gun a bit.
Like I understand killing a serial rapists/sexual assualters, but this may be taking some information out of context. Like, I know it's meant to imply that this was a case of serial domestic abuse, but what if she misunderstood the situation and this was like a one-time thing and he didn't actually hit her? I think she should have gathered more information first because if they actually did love each other and were generally supportive, but the guy just exploded from the pressure and chewed her out one day, I don't think we'd be rooting for her as much
@TheLaidBackMan Easier said then done. Soldiers have to deal the stress of knowing they're killing someone's son, brother, friend, loved one, etc. Hence the phrase: afraid to shoot strangers.